U.S. and Mexican authorities appeared to be collaborating closely on security measures before the president's visit.
Two of the eight prototypes, each 30 feet tall, have see-through fencing, both at ground level.
"According to the Center for Immigration Studies, the $18 billion wall will pay for itself by curbing the importation of crime, drugs and illegal immigrants who tend to go on the federal dole", Trump tweeted.
Trump repeated his insistence that law enforcement personnel should be able to see through the structure so that they could monitor criminal cartels that might be "two foot away" on the Mexican side.
The president's arrival was awaited in the area by a cluster of police, chanting protesters and supporters clad in campaign gear, waving American flags.
President Donald Trump has arrived in San Diego, where he'll be touring the prototypes for his stalled border wall.
In Beverly Hills, a protest meant to "resist" Trump and planned for 5 p.m.in Beverly Gardens Park was being hosted by a group called "ICE Out of LA", according to its Facebook page. "No wall!" near the San Ysidro crossing, where tens of thousands of people enter the USA daily from Tijuana, Mexico, many on their way to work or school in San Diego.
"And people are gonna start to move pretty soon", he said. Others say they understand why people want to secure the border more.
Trump is talking about sanctuary city policies during his visit to San Diego and inspecting border wall prototypes before heading to L.A. The terminal is located a few miles from the wall prototypes.
Faulconer, writing in The San Diego Union-Tribune, also said San Diego police work to protect everyone regardless of immigration status, an apparent dig at Trump's push to target illegal immigration.
"You see, in California we are focusing on bridges, not walls", Brown said in a letter sent to Trump. We are sick and exhausted of our dreams being stolen by illegal sanctuary policies and the criminal politicians that support them in our state.
President Trump broke with standard practice Tuesday, flying to California without any lawmakers from the state. The protest's Facebook page now lists the start time as 5 PM, though the president's plans remain so unpublicized that the rally's start time has been modified on the page throughout the day.
The scene is quiet along the U.S. -Mexico border south of San Diego, where protests are expected when President Donald Trump arrives.
Security is sure to be tight, although it is unknown to what extent Trump might expose himself in examining the prototypes. "Traitor", said one. "Moron", said another - a reference to Secretary of State Rex Tillerson, who reportedly used that term to describe President Trump past year, and who was abruptly fired earlier Tuesday morning.
The Justice Department last week sued to block a trio of California laws created to protect people living in the USA illegally.
"This is an environmental catastrophe, on top of a misallocation of government resources that could be used for health care or social services", Cody Petterson, president of the San Diego County Democrats for Environmental Action, said of the wall.
Trump reviews border wall prototypes on Tuesday in the outskirts of San Diego.
Said Trump: "If you didn't have walls over here you wouldn't even have a country". Trump has insisted Mexico pay for the wall.
Trump's visit comes just days after his Justice Department sued to block California laws created to protect people living in the USA illegally.
The largest planned anti-Trump protest is scheduled at a San Ysidro Catholic church that offers a full view of the nearby border.